Hi, I had gone through your question and understand your concerns. I am not sure what CBT Calsca os. You may have misunderstood something. Abdominal pain may be sign of many issues and it is good that he has done all these tests but also, he should do some endoscopic tests to see inside the bowel and colon. So he should definitely do colonoscopy as the next step since MRi cant visualize inner parts of colon in which may be a problem such as inflammaory bowel disease or tumors or IBD for example. Most causes are not serious but extensive wotk up is required. Yellow eyes are signs of hogh bilirubin and liver damage so he must see if there i viral or autoimmune hepatitis if hus iver morphology is fine on MRI scan. Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions.